Mohamed, a resident, said: "Anybody who has any means of fleeing the area has left."

The UN refugee agency said last week that more than 321,000 people had fled the capital since February 1, but clan elders told AFP news agency that figure could now be closer to 400,000 with the exodus of thousands more over the past six days.

"The fighting is heavier [than] yesterday, the rivals are exchanging machine gun, mortar and anti-aircraft fire."

At least 267 people have died since the clashes began last Wednesday, the Elman Peace and Human Rights Organisation, a local group that tracks the number of casualties, said.

Casualties increasing

Hussein Said Korgab, a spokesman for the Hawiye clan, Mogadishu's largest, said: "The fighting is very heavy and the casualties are steadily increasing everyday. The Ethiopian forces are hitting civilians indiscriminately."

This week's fighting alone has displaced at least tens of thousands of people and destroyed expensive property, he added.

"At least 70,000 [people] have evacuated their homes. Property worth $500m has been destroyed. The Ethiopian and government forces will take ultimate responsibility for all this mess," he said.

Hundreds of civilians, clutching their personal belongings, took advantage of relative calmness in southern Mogadishu and fled their neighbourhoods.

Bur Dheere, a mother-of-three, said: "We have no place to stay in this town. Everywhere in Mogadishu is the same - death. We are running away until we reach a safer place."

National instability

Ethiopian troops helped Somalia's interim government push the Union of Islamic Courts from the country's south and central regions in January.

Fighting continues months after the defeat ofthe Islamic courts [AFP]

Since then, fighting has steadily grown worse as remanents of the movement backed by Hawiye clansmen continue to fight, vowing to defeat the interim government and drive out foreign forces from the country.

On Monday, Ali Mohamed Gedi, Somalia's Ethiopian-backed prime minister, said that his government was winning the battle but called for greater support from the international community.

On the Mogadishu-based Shabelle radio, he said: "Until the terrorists are wiped out from Somalia, the fighting will go on."

"If we do not get international support the war may spread throughout the region and Africa," he said. "These terrorists want to destabilise the whole region."

Somalia has lacked an effective government ever since Barre's removal from power touched off a deadly power struggle that has defied more than 14 attempts to create a government that can stabilise the country of about 10 million people.